need inexpensive linear motion

[sandiegoman]

I need an inexpensive way to get about 1" - 2" of linear motion. I have a few ideas on how I can do this, but was hoping to find some inexpensive pre-made components with gear boxes or whatever. Would need to push/pull approximately 5 lbs of pressure. <p>I am currently using a cam driven system using a standard dc motors, but am looking for a smaller and inexpensive alternative.<p>Any ideas?

[rshayes]

Sometimes the actuators for automatic car door locks and car windows show up on the surplus market. These seem to be a geared down motor driving a rack and pinion to get linear motion.<p>Another possibility is the actuator for a retractable radio antenna. This might be available in surplus or as an aftermarket item.

[bwts]

solenoids maybe<p>B

[dribach]

i think it's have to be a pretty hefty solenoid to produce 5 lbs of force... i'd definitely go with a servo, possibly from a hobby shop (to be used on large RC planes maybe), or one made from stephen's suggestions

[ptribbey]

I would use the 12V motor and leadscrew out of an electric automobile seat obtained from a local auto recycler. There are usually 2 or more motors in each seat and are capable of producing gobs of tourque and thereby pounds of pressure.

[dribach]

ooo, creative

[Daggs]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Mr Bwtz:
solenoids maybe<p>B<hr></blockquote><p>concur. A flipper solenoid from a pinball machine provides quite a bit of force. Activated by 50V.

[sandiegoman]

Thanks guys! I have tested a few of these in the past and they seem to work out fairly well in my larger project... What I am looking for now is to get the most torque with the smallest amount of room... <p>I need some type of small gear box so I can use some inexpensive hobby motors geared down to get more torque and slow the revolutions. I think I need at max 120RPM on the output. Any ideas on where I can get some small gear boxes to convert to linear as well as increase torque? Kits, spare-parts, etc... anything that will get me about 1-2" of motion with fairly good torque.<p>Thanks!!!!

[rshayes]

Tamiya makes a series of DC motor and gearbox kits. These are available in several versions, using spur gears, worm gears, and planetary gears. Each model can be assembled with several gear ratios. Output torque may be limited by the gearbox construction, since some of the gearboxes are made with plastic sides and use plastic gears.<p>Fry's Electronics has these kits in their hobby kit area. They have at least one store in the San Diego area. Hobby shops may also stock these kits.

[toejam]

allelectronics.com has a motorized pot that uses a a rack combined with a small gearmotor. it may work for your application,

[Lin Farquhar]

try your local auto parts or electronic store for car central locking actuators. Cheap and heaps of thrust though draw a fair bit of current at 12V. Also require logic circuitry since no limit switching, they are just a motor, reduction box and rack.<p>Regards, LF

[dacflyer]

ok, heres my idea for a ton of torque
get you some threded rod,,,adapt it to a B&D or SKILL TWIST cordless screw driver., use the head strip the batteries and such..and use just the gear head...maybe this will work for you? just an idea its small and compacked..

[cato]

I have no idea how much force you will get from it....probably NOT 5lbs.....however....consider opening a Crest Spinbrush. Inside you will find a DC motor and a simple gearing arrangement to turn the rotation of the motor into a linear reciprication of about 1/4 inch...I think if you use a different (i.e., bigger) gear and offset (You'll understand when you open the brush) you can get a slower, more forcefull linear motion.